Objective: To evaluate the efficacy of a regimen of vaginal misoprostol in causing the complete expulsion of first-trimester missed abortions, or alternatively dilating the cervix for surgical evacuation, Method: Seventy-four women with a transvaginal ultrasound diagnosis of a first-trimester missed abortion and no more than slight vaginal bleeding were consecutively enrolled. Misoprostol (600 mug) was administered vaginally and repeated 4 h later if necessary. Surgical evacuation was performed when complete expulsion was not documented on the ultrasound 10-12 h after treatment. Results: Complete medical evacuation occurred in 42 women (56.8%), 11 (14.9%) of which required only one dose. Seventy women (94.6%) experienced abdominal pain, 73 (98.6%) vaginal bleeding, 10 (13.5%) nausea, 4 (5.4%) vomiting, 5 (6.8%) diarrhea, and 4 (5.4%) transient hyperthermia. There was one case of heavy vaginal bleeding requiring emergency surgical evacuation, and one re-admission for incomplete abortion at 30 days. All but 4 (5.4%) women had permeable cervices at the time of surgery. Conclusion: The described regimen of vaginal misoprostol is safe and reasonably effective in inducing complete evacuation in missed abortions. When this does not occur, it almost always provides adequate cervical dilatation for surgery. (C) 2000 International Federation of Gynecology and Obstetrics. All rights reserved.